Scientists have figured out how to turn sewage into biofuel to reduce airplane emissions by 70%; They created a new sustainable version of jet fuel using biomass and agricultural waste. A new technology could turn wastewater into biofuel, cutting aircraft emissions by 70% compared to traditional jet fuel, scientists say.

Clean aviation fuel (SAF) currently accounts for less than 1% of the fuel used in the aviation industry, but as aviation accounts for 2.5% of global carbon dioxide emissions, there is an urgent need to find greener fuel solutions.

While the main aviation fuel options use petroleum, alternative options rely on fats or mineral oils. In a study published April 25 in the journal ACS Sustainable Chemistry and Engineering, scientists describe a technology that converts wastewater from breweries and dairy farms into essential components for SAF: volatile fatty acids.

The scientists used methane delayed anaerobic digestion (MAAD), a process first developed by Meltem Urgun Demirtaş, chief of the Sustainable Materials and Processes Division at Argonne National Laboratory. In this process, instead of traditional wastewater treatment, bacteria break down the organic matter in the wastewater through anaerobic digestion, converting the wastewater into butyric and lactic acids. These acids can then be converted into SAF, scientists say.

But the process also produces lactic acids, which limit SAF production and even reduce the carbon efficiency of conversion from volatile fatty acids to SAF. To overcome this problem, scientists have also developed an electrochemical separation method that removes organic compounds from wastewater.

The end result was the development of an on-site product recovery process that eliminates desired waste in complex mixtures using membrane separation. These techniques, combined with anaerobic fermentation, allowed the team to create sustainable microbial communities that produced large amounts of butyric acid.

Argonne National Laboratory scientists will continue to work to improve the sustainability of their results and may even explore other raw materials that can be used with this technology. This effort was funded by the Bioenergy Technology Division of the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy. It is hoped that with the research funding, scientists will achieve their goal of commercializing the process and scaling it to create enough SAF to meet 100% of the commercial sector’s demand.

Previously, scientists were already paying attention to the negative impact of wastewater on ecosystems. Algal blooms caused by sewage “could alter biodiversity,” says Anne Jungbluth, a biological sciences researcher at the National History Museum in the United Kingdom. Changes in biodiversity can have detrimental effects on entire rivers.

“Both wastewater streams are rich in organic matter, and treating them using conventional methods is a carbon-intensive process,” said Taemin Kim, an energy systems analyst at Argonne University. “Using our technology, we are not only cleaning up these waste streams, but also producing a low-carbon, sustainable fuel for the aviation industry.”

The on-site product regeneration process using membranes reduces greenhouse gas emissions by 70% while remaining a cost-effective end product. Greenhouse gases cause climate change by trapping heat, causing a ripple effect across different biomes, according to the U.S. Environmental Protection Agency. By greatly reducing their numbers through this process, Argonne scientists can take the first steps in combating climate change and eliminating the need for harmful fuels.